Basf Aktiengesellschaft

Badische Anilin- & Soda-fabrik Aktiengesellschaft

Richard Krabetz

Gerd Duembgen

Franz Merger

Heinz Engelbach

Fritz Thiessen

Matthias Schwarzmann

Carl-Heinz Willersinn

Gerd Fouquet

Friedbert Nees

Ulrich Lebert

Walter Herrmann

Walter Frey

Ulrich Hammon

Herbert Vogel

Karl-Heinz Boehning

Peter Palm

Heinrich Spahn

Peter Bassler

Franz J Broecker

Karl Baer

Norbert Scholz

Karl Sommer

Ekhart Lucas

Gerd-Juergen Engert

Walter Beitelschmidt

Friedbert Hofmann

Hermann Spitzl

Herbert Vogal

Michael Jaeger

Compositions of the formula Mo.sub.12 P.sub.a V.sub.b X.sup.1 c X.sup.2

Compositions of the formula MO.sub.12 P.sub.a V.sub.b X.sup.1.sub.c

Methacrylic acid can be prepared with advantage by gas phase oxidation of methacrolein or isobutyraldehyde over Mo- and P-containing catalysts at from 250.degree. to 400.degree. C. with cooling of the hot reaction gas to below 100.degree. C., absorption of the methacrylic acid in a water-operated absorption column, at below 100.degree. C. and partial recycling into the oxidation reactor after admixture of methacrolein or isobutyraldehyde and oxygen by feeding a quantity of methacrolein or isobutyraldehyde equal to the quantity of methacrolein or isobutyraldehyde consumed in the reaction in liquid form together with a polymerization inhibitor into the reactor gas in the lower two-thirds of the absorber column and upstream of the feed point for the fresh methacrolein or isobutyraldehyde or down-stream of the absorption column splitting off the reactor off-gas a side stream which is washed in a wash column operated with water at &lt;10.degree. C. to remove unconverted methacrolein or isobutyraldehyde which is fed as an aqueous solution to the top of the absorption column.

Preparation of methacrylic acid

Oxidation catalysts of the general formula

Process and catalyst for the preparation of methacrylic acid

A molded catalyst for reactions carried out under heterogeneous catalysis consists of a catalytically active material shaped into hollow cylinders, or of an inert carrier which is shaped into hollow cylinders and onto which catalytically active material is applied the external diameter of the hollow cylinders being from 3 to 20 mm, the internal diameter being from 0.1 to 0.7 times the external diameter and the length being from 0.2 times to twice the external diameter. The end faces of the hollow cylinder are curved so that the radius of curvature is from 0.4 to 5 times the external diameter. The novel catalysts are particularly useful for partial oxidation in the gas phase.

Molded catalyst for reactions carried out under heterogeneous catalysis

A catalyst which is free from alkali metal compounds and alkaline earth metal compounds, contains palladium and lead as active constituents and is supported on a carrier which contains two or more of the oxides ZnO, Al.sub.2 O.sub.3, La.sub.2 O.sub.3 and TiO.sub.2, and the use of this catalyst for the preparation of methyl methacrylate from methacrolein, methanol and oxygen.

Preparation of methyl methacrylate from methacrolein

Production of acrylic acid by oxidation of acrolein with gas containing oxygen in the gas phase at elevated temperature in the presence of a catalyst which, in addition to oxygen, consists essentially of (a) molybdenum, (b) tungsten, (c) vanadium and (d) iron and/or copper. The atomic ratio of molybdenum:tungsten:iron and/or copper is 1 to 20:0.01 to 10:1 and the atomic ratio of vanadium:molybdenum is 0.2 to 6:6. Acrylic acid is an important starting material for the production of high polymers.

Production of acrylic acid by oxidation of acrolein

Preparation of methacrylic acid and catalyst therefor

Catalysts for the preparation of carboxylates from an aldehyde and an alkanol in the presence of oxygen, which contain palladium and lead as active components, these being present on a carrier containing zinc oxide, and the palladium being applied as a palladium salt in a solution containing hydrochloric acid and then being liberated by reduction, and whose carrier consists solely of zinc oxide, are particularly active and selective.

Catalyst for the preparation of methyl methacrylate

.alpha.-Alkylacroleins are prepared by a process wherein an alkanal is reacted with formaldehyde in the presence of a secondary amine and in the presence or absence, of an acid, in the liquid phase, under superatmospheric pressure and at above 150.degree. C., for not more than 25 minutes. The .alpha.-alkylacroleins obtainable by the process are useful starting materials for dyes, drugs and pesticides.

Process for the preparation of .alpha.-alkylacroleins

Oxidation catalysts which in addition to oxygen ions, with or without NH.sub.4.sup.+ ions, contain molybdenum, tungsten, phosphorus and antimony as basic components, in the atomic ratio Mo:W:P:Sb=12:0.1-3:0.1-4:0.1-3, and which are prepared in a conventional manner by combining molybdenum, phosphorus, antimony and tungsten compounds in aqueous solutions or suspensions, removing the water and calcining the residues, the combination being carried out at chloride ion concentrations of less than 0.3 mole per mole of molybdenum and in the presence of ions of monocarboxylic acids of 1 or 2 carbon atoms, dicarboxylic acids or hydroxycarboxylic acids, are particularly suitable for the gas phase oxidation of methacrolein to methacrylic acid.

Oxidation catalyst, especially for the preparation of methacrylic acid

An oxidation catalyst wherein the catalytically active component has the general formula

Preparation of methacrylic acid by gas phase oxidation of methacrolein

A coated catalyst comprising (a) an inert carrier having particles of not less than 100 .mu.m diameter and a surface area of up to 20 m.sup.2 /g and (b) a coating which contains the catalytic material and adheres firmly to the outer surface and to the edge zone, near the surface, of the carrier particles, can be prepared by applying the catalytic material as a 10-70% strength suspension in water to the agitated carrier particles, which are at below 70.degree. C., if the suspension is sprayed, at a constant rate of from 0.01 to 2.0 kg of active material/hour/liter of carrier onto the carrier particles, while at the same time uniformly passing from 0.1 to 12 m.sup.3 (S.T.P.)/hour/liter of carrier of an inert gas at from 20.degree. to 300.degree. C. over the carrier particles, under conditions such that the water only evaporates incompletely but the water content of the resulting coating is less than the maximum degree of saturation of the catalytic material.

Preparation of coated catalysts

Acrolein and methacrolein are prepared advantageously by oxidizing propylene or isobutylene, respectively, with an oxygen-containing gas mixture under conventional conditions over a supported catalyst possessing a firmly adhering coating, from 150 to 1,500 .mu.m thick, which contains calcined catalytic material based on molybdenum oxide and has a carrier core with a surface area of less than 15 m.sup.2 /g and a diameter of more than 100 .mu.m, if a coated catalyst is used which has been prepared by applying calcined catalytic material having a particle size of from 0.1 to 300 .mu.m, in an amount of from 1 to 40 g/min/liter of carrier and water in a weight ratio of catalytic material to water of from 1:1 to 8:1, continuously and separately from one another, each at a constant speed, at below 100.degree. C. to vigorously agitated carrier particles which may or may not have been premoistened with water in an amount of up to 95% of the water absorbency of the particles, the prepartion of the catalyst being carried out in such a way that the water content of the coating which forms is less than the maximum degree of saturation of the catalytic material.

Preparation of .alpha.,.beta.-olefinically unsaturated aldehydes of 3 or

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Richard Krabetz